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Debates · Diet and obesity causes

Should most adults deliberately eat a high-fiber diet to improve gut microbiome function and overall health?

6 shows · 9 speakers · published Oct 7, 2026 · updated Oct 19, 2026

The debate

Podcasts debate whether most adults should deliberately eat high‑fiber diets for gut microbes and health, avoid more fiber, or match fiber to individual tolerance. Crawford (The Diary Of A CEO) and Pasricha (Science Vs) argue that fiber feeds gut microbes and supports bowel habits and long‑term health risks. Bosworth (The Diary Of A CEO) and Jockers (Dr. Jockers Functional Nutrition) question universal fiber targets and describe adults who feel better with little or no fiber since late 2025.

Where each side stands

Yes, most adults should eat plenty of fiber for better gut and overall health.

Dr Natalie Crawford (The Diary Of A CEO) · Peter Attia (The Peter Attia Drive) · Cynthia Thurlow (Dr. Jockers Functional Nutrition) · Dr. Marie-Pierre St-Onge (Huberman Lab) · Dr Andy Galpin (The Diary Of A CEO) · Trisha Pasricha (unPAUSED with Dr. Mary Claire Haver) · Dr. Trisha Pasricha (Science Vs)

Crawford says fiber from food is the best nutrient for the gut microbiome. Pasricha links high‑fiber diets to lower dementia and cardiovascular disease risk through short‑chain fatty acids produced when microbes ferment fiber. Attia (The Peter Attia Drive) describes soluble viscous fibers that gel in the gut, slowing gastric emptying, blunting blood sugar spikes, and modestly lowering cholesterol. Pasricha says you eat fiber to feed gut bacteria and recommends 25 grams for women under 50 and 21 grams over 50.

14 claims, in their words
  • “the food that you're putting into your body is the best nutrients for your gut microbiome is fiber.”
    Dr Natalie Crawford · The Diary Of A CEO · 2025-10-27 · 1:47:03 nothing cited
  • “Not all fibers are created equal ... some fibers provide primarily microbiome support because they're actually fermented by gut microbiomes. Some fibers Can improve blood sugar ... and others simply bulk up stool.”
    Peter Attia · The Peter Attia Drive · 2025-11-10 · 10:45 nothing cited
  • “Viscous fiber is able to absorb water and create a gel, a viscous gel in the gut. ... this can lead to slower gastric emptying. It can blunt blood sugar spikes, contributes to lower cholesterol, though I would argue not so meaningfully that we should rely on this for lipid management.”
    Peter Attia · The Peter Attia Drive · 2025-11-10 · 12:42 nothing cited
  • “Insoluble fibers obviously do not dissolve in water. ... These are the ones that I talked about earlier. They are essentially there to bulk up stool, mechanically stimulating the gut lining to release water and mucus, to dilute irritants and toxins in the colon, and speed up intestinal transit. So most insoluble fibers are also not fermented by gut bacteria.”
    Peter Attia · The Peter Attia Drive · 2025-11-10 · 12:08 nothing cited
  • “if you suddenly go from 5 to 10 grams to 30, your microbes can't acclimate as quickly. So doing it slowly over time is really important.”
    Cynthia Thurlow · Dr. Jockers Functional Nutrition · 2026-04-28 · 34:18 nothing cited
  • “there was also habituation. You don't go from consuming six grams of fiber per day to 25. They ramped”
    Dr. Marie-Pierre St-Onge · Huberman Lab · 2026-06-08 · 1:08:37 nothing cited
  • “But they bring so much more. Right? So yes, there's fiber in fruits and vegetables, but there's also all sorts of polyphenols, right? All sorts of non-nutrient components that themselves may have benefits for health that we don't fully understand yet that feed your gut, that are maybe just as relevant, that may enhance fiber's impact on health.”
    Dr. Marie-Pierre St-Onge · Huberman Lab · 2026-06-08 · 1:52:28 nothing cited
  • “Fiber, depending on the type of cholesterol, will actually bind to the cholesterol and clear it from the system.”
    Dr Andy Galpin · The Diary Of A CEO · 2026-08-13 · 1:11:51 nothing cited
  • “If you eat more fiber, you're meeting your fiber goals, you're going to poop more often and you should embrace that side of you.”
    Trisha Pasricha · unPAUSED with Dr. Mary Claire Haver · 2026-10-06 · 11:15 nothing cited
  • “Fiber is their food, right? And again, fiber is not just one thing. ... Your gut and those bacteria want a diversity of plant-based fibers ... for women. That is 25 grams if you're under 50. It's 21 if you're over 50.”
    Trisha Pasricha · unPAUSED with Dr. Mary Claire Haver · 2026-10-06 · 1:17:27 cites a number
  • “if I've been living with a microbiome that is not used to fiber. You can't suddenly be like, whoa, like over the system. If you're going to cause gas, you're going to cause bloating, you may well cause diarrhea. But not if you start low and go slow.”
    Trisha Pasricha · unPAUSED with Dr. Mary Claire Haver · 2026-10-06 · 1:23:35 personal experienceThe number of people who have come to my clinic who have been like, I fiber maxed, I live to regret it
  • “if we didn't have those microbes and we weren't producing those short chain fatty acids, they've done these studies. I mean, this is the reason why high fiber diet, it's associated with lower risk of dementia, of cardiovascular disease.”
    Dr. Trisha Pasricha · Science Vs · 2026-10-15 · 38:50 cites a studystudies on short chain fatty acids
  • “You eat fiber to feed your microbes. Your microbes that are living in your microbiome, they need fiber to survive.”
    Dr. Trisha Pasricha · Science Vs · 2026-10-15 · 37:11 nothing cited
  • “once you are meeting your fiber goals, assuming there's not something else going on, like with pelvic floor dysfunction, it's an in and out job.”
    Dr. Trisha Pasricha · Science Vs · 2026-10-15 · 40:00 personal experienceI will say like if you take psyllium, everything just becomes soft, easy, effortless

No, adults generally should not increase fiber intake; it is unnecessary or harmful.

Annette Bosworth (The Diary Of A CEO)

Bosworth claims fiber's main effect is producing gas and that it damages a healthy protective gut mucus layer instead of improving the microbiome.

1 claim, in their words
  • “Fibers for farting. So you're looking at a gut biome, right? And so tell me what you think that is.”
    Annette Bosworth · The Diary Of A CEO · 2025-11-24 · 1:07:41 personal experiencemany of my carnivore patients

Optimal fiber intake varies; some individuals thrive with low-fiber or carnivore diets.

David Jockers (Dr. Jockers Functional Nutrition)

Jockers says fiber tolerance follows a bell curve where most adults handle a moderate amount, while some need much less or much more. Jockers explains that people who feel more energy, better stools, and better digestion and brain function on very high fiber should stay with that higher‑fiber pattern.

2 claims, in their words
  • “with fiber, it's kind of like a bell curve. Most of us are somewhere around the middle where we can handle a, you know, a certain amount ... some people need less, right? They actually need less, and they're the people that seem to do well on carnivore diets”
    David Jockers · Dr. Jockers Functional Nutrition · 2026-04-28 · 38:20 nothing cited
  • “If you're somebody that thrives on a very high fiber diet, you just have more energy, you have better stools, better digestive health, better brain function, then stick with a higher fiber diet until, you know, you don't feel as good.”
    David Jockers · Dr. Jockers Functional Nutrition · 2026-09-25 · 12:41 nothing cited
What each side never hears

Listeners of “No, adults generally should not increase fiber intake; it is unnecessary or harmful.” have not heard (5 arguments)

Pasricha's point that high‑fiber diets correlate with lower dementia and cardiovascular disease risk via microbe‑produced short‑chain fatty acids has not been presented on these shows. Attia's explanation that viscous soluble fiber gels in the gut, slowing gastric emptying, blunting blood sugar spikes, and lowering cholesterol is absent from these discussions. Galpin (The Diary Of A CEO) states that certain fibers bind to cholesterol and clear it from the body, a point not raised for listeners here. St‑Onge (Huberman Lab) describes that fruits and vegetables supply polyphenols and other components that may benefit health and work alongside fiber, a view missing here.

5 unanswered arguments, in their words
  • “if we didn't have those microbes and we weren't producing those short chain fatty acids, they've done these studies. I mean, this is the reason why high fiber diet, it's associated with lower risk of dementia, of cardiovascular disease.”
    Dr. Trisha Pasricha · Science Vs · 2026-10-15 · studies on short chain fatty acidsthis week
  • “Viscous fiber is able to absorb water and create a gel, a viscous gel in the gut. ... this can lead to slower gastric emptying. It can blunt blood sugar spikes, contributes to lower cholesterol, though I would argue not so meaningfully that we should rely on this for lipid management.”
    Peter Attia · The Peter Attia Drive · 2025-11-10 · unanswered for 49 weeks
  • “But they bring so much more. Right? So yes, there's fiber in fruits and vegetables, but there's also all sorts of polyphenols, right? All sorts of non-nutrient components that themselves may have benefits for health that we don't fully understand yet that feed your gut, that are maybe just as relevant, that may enhance fiber's impact on health.”
    Dr. Marie-Pierre St-Onge · Huberman Lab · 2026-06-08 · unanswered for 19 weeks
  • “Fiber, depending on the type of cholesterol, will actually bind to the cholesterol and clear it from the system.”
    Dr Andy Galpin · The Diary Of A CEO · 2026-08-13 · unanswered for 9 weeks
  • “if I've been living with a microbiome that is not used to fiber. You can't suddenly be like, whoa, like over the system. If you're going to cause gas, you're going to cause bloating, you may well cause diarrhea. But not if you start low and go slow.”
    Trisha Pasricha · unPAUSED with Dr. Mary Claire Haver · 2026-10-06 · The number of people who have come to my clinic who have been like, I fiber maxed, I live to regret itunanswered for 1 week

Listeners of “Yes, most adults should eat plenty of fiber for better gut and overall health.” have not heard (1 argument)

Listeners of these shows have not heard Bosworth's claim that fiber mainly causes gas and strips away a beneficial gut slime layer instead of helping the microbiome.

1 unanswered argument, in their words
  • “Fibers for farting. So you're looking at a gut biome, right? And so tell me what you think that is.”
    Annette Bosworth · The Diary Of A CEO · 2025-11-24 · many of my carnivore patientsunanswered for 47 weeks

Listeners of “Optimal fiber intake varies; some individuals thrive with low-fiber or carnivore diets.” have not heard (7 arguments)

Pasricha's explanation that we eat fiber mainly to feed gut microbes, which depend on it to survive, has not been covered on these shows. Bosworth's view that fiber tears down a protective gut mucus layer rather than supporting the microbiome is also missing for these listeners. Attia's account of viscous soluble fiber forming a gel that slows gastric emptying, blunts blood sugar spikes, and lowers cholesterol does not appear in their discussions. Pasricha's claim that high‑fiber eating is associated with lower dementia and cardiovascular disease risk through short‑chain fatty acids is not presented to them.

7 unanswered arguments, in their words
  • “Viscous fiber is able to absorb water and create a gel, a viscous gel in the gut. ... this can lead to slower gastric emptying. It can blunt blood sugar spikes, contributes to lower cholesterol, though I would argue not so meaningfully that we should rely on this for lipid management.”
    Peter Attia · The Peter Attia Drive · 2025-11-10 · unanswered for 49 weeks
  • “Fiber, depending on the type of cholesterol, will actually bind to the cholesterol and clear it from the system.”
    Dr Andy Galpin · The Diary Of A CEO · 2026-08-13 · unanswered for 9 weeks
  • “Fibers for farting. So you're looking at a gut biome, right? And so tell me what you think that is.”
    Annette Bosworth · The Diary Of A CEO · 2025-11-24 · many of my carnivore patientsunanswered for 47 weeks
  • “But they bring so much more. Right? So yes, there's fiber in fruits and vegetables, but there's also all sorts of polyphenols, right? All sorts of non-nutrient components that themselves may have benefits for health that we don't fully understand yet that feed your gut, that are maybe just as relevant, that may enhance fiber's impact on health.”
    Dr. Marie-Pierre St-Onge · Huberman Lab · 2026-06-08 · unanswered for 19 weeks
  • “You eat fiber to feed your microbes. Your microbes that are living in your microbiome, they need fiber to survive.”
    Dr. Trisha Pasricha · Science Vs · 2026-10-15 · this week
  • “if I've been living with a microbiome that is not used to fiber. You can't suddenly be like, whoa, like over the system. If you're going to cause gas, you're going to cause bloating, you may well cause diarrhea. But not if you start low and go slow.”
    Trisha Pasricha · unPAUSED with Dr. Mary Claire Haver · 2026-10-06 · The number of people who have come to my clinic who have been like, I fiber maxed, I live to regret itunanswered for 1 week
  • “if we didn't have those microbes and we weren't producing those short chain fatty acids, they've done these studies. I mean, this is the reason why high fiber diet, it's associated with lower risk of dementia, of cardiovascular disease.”
    Dr. Trisha Pasricha · Science Vs · 2026-10-15 · studies on short chain fatty acidsthis week
Bottom line

Pro‑fiber speakers lean on claims that fiber feeds gut microbes and that intake links to lower dementia and cardiovascular disease, which opponents do not discuss. Opponents focus on fiber causing gas and mucus disruption and on varying tolerance, while pro‑fiber speakers focus on microbiome nutrition and long‑term disease links.

1 argument the other side has addressed
Argument
“You eat fiber to feed your microbes. Your microbes that are living in your microbiome, they need fiber to survive.”
Dr. Trisha Pasricha · Science Vs · 2026-10-15 · 37:11
Addressed by
“Fibers for farting. So you're looking at a gut biome, right? And so tell me what you think that is.”
Annette Bosworth · The Diary Of A CEO · 2025-11-24 · 1:07:41 · different episodes
What changed

Published because: 6 shows, 3 positions, 353 days of debate. Questions publish only when claims come from at least three shows, at least two positions are held by different people, and the debate has lasted two weeks.

Pairs are matched by content across different episodes and shows; no exchange between these speakers took place unless both quotes come from the same episode.

The prose on this page is written by a model from the quotes shown, and every sentence of it rests on quotes you can open; sentences that could not be traced to a quote were removed before publishing. Positions are placed from each speaker's own words. Evidence labels say what the speaker cited, never whether it is true.

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